Constructed between 1956 and 1965, Grahamstown Dam is the Hunter’s largest drinking water supply dam. It supplies more than half of the drinking water our customers use on a regular basis, even more during periods of drought and peak demand.
It’s an off-river storage source that extracts water from the Williams River and receives inflow from its own catchment.
| Grahamstown Dam | |
|---|---|
| Catchment area | 97km2 |
| Dam volume | 182,305ML (million litres) |
| Average depth | 9 metres |
| Surface area | 2800 hectares |
| Annual rainfall | 1125mm (Williamtown) |
| Areas supplied | Lower Hunter, approximately 40% of volume |
| Land use breakdown of catchment | 39% Hunter Water freehold, 39% rural, rural residential or urban, 22% State Forest. |
As part of our commitment as a responsible dam owner, we visually inspect the dam each day, and complete periodic assessments of safety, risk, and maintenance to ensure the dam continues to operate safely. In late June 2024 we finished the most detailed risk assessment ever completed for Grahamstown Dam.
Our water levels drop faster than most other major Australian urban centres during hot, dry periods because we have shallow water storages and high evaporation rates.
The catchment is primarily located on the northern and eastern shores of the dam.
To the north of the catchment, Seven Mile Creek fills the dam with run-off from small farms and other minor developments. Approximately 75 per cent of total catchment run-off comes from the northern part of the catchment.
Run-off from the east comes directly from the urban settlement of Medowie through the Campvale Swamps. Water is pumped into the dam via the Campvale Pump Station and finally spills at the Irrawang Spillway.
We work closely with landowners and residents in the Grahamstown catchment area to improve the quality of water draining into Grahamstown Dam.
Grahamstown Dam is classified as an off-river storage facility, storing raw water that’s pumped from the Williams River at Seaham Weir through the Balickera Canal, raised approximately 15m at the Balickera Pump Station and then flows through the Balickera Canal and Tunnel into the northern end of Grahamstown Dam. On average, 50 per cent of inflow to Grahamstown Dam is pumped from the Williams.
We monitor water quality in the Williams River for nutrients before transferring water to Grahamstown Dam. Like most Australian rivers, the Williams is highly influenced by climatic conditions and is consequently highly variable in flow and water quality. Flow and water quality are assessed against pumping rules to minimise the nutrient load transferred to the dam.
Finnan Park is located at the southern end of Grahamstown Dam off Richardson Road and has picnic facilities overlooking the dam. Facilities include parking, water taps, toilets, children's playground, picnic shelters and picnic tables. Private bookings of the Finnan park facilities are not available.
Finnan Park is open during daylight hours only. The gates are locked overnight.
To protect drinking water quality, public access is not permitted onto Grahamstown Dam or its catchment, but there is an adjacent picnic facility that is open to the community.
We recently revealed a mural at our public recreation area at Grahamstown Dam, with the Aboriginal artwork highlighting our community’s deep connection with water.
As the dam is a drinking water supply source for the Hunter Region, there are restrictions in place for visitors to Finnan Park. These include:
The penalties for non-compliance and further information can be found on the Public access to dams and catchments page.